1. Field of the Invention
The present invention relates to a liquid crystal display device.
2. Description of the Related Art
In recent years, liquid crystal display devices are in use as a unit of a digital television set, however, they are devaluated due to responses inferior to those of CRTs in displaying moving images. As a main cause thereof, it is known that a displacement is caused during one frame between an image on the same screen continuously displayed and an eye movement. As methods to obtain a display of the same level as of CRT, there have been presented a method in which a black screen is inserted and a method in which the flashing cycle (or a repeating cycle of a light state and a dark state) of a back light is made to coincide with a display cycle. However, both the methods are forced to lower the display luminance of completely white, having not yet reached to a wide practical use.
Further, in Japanese Patent Application Laid-Open No. 2000-338464 (patent document 1), there is described that, in a display element displaying images of plural frames in a second, a single frame F0 is displayed by being divided into at least two fields F1, F2, in which at least in a sub field 1F of the single field F1, a desired image is displayed at a first luminance Tx and, in a remaining single sub-field 2F, an image being practically the same as the image displayed at the first luminance is displayed at a second luminance Ty being smaller than the first luminance and larger than 0 (zero).
As an art realizing a higher luminance and a moving-image display performance together, it is conceivable to perform halftone display by driving the panel at a double speed. However, in the liquid crystal display device adopting the art, there exist two problems as will be described below. First, an insufficient resolution in the halftone display. Second, a ghost image at a luminance change is not resolved especially between low-tones.